Air circulating apparatus for use in tunnels

ABSTRACT

The air circulating apparatus comprises a movable carriage in the form of an arch, an air supply duct mounted on the carriage and provided with an air discharge port for forming an air curtain across the tunnel, and an exhaust duct mounted on the carriage and projecting forwardly. The carriage is provided with crawlers so as to be movable. A sufficient space is left beneath the carriage and the air supply duct for free passage of vehicles.

United States Patent 1191 Yoshikawa et a1.

1451 Nov. 18, 1975 1 1 AIR CIRCULATING APPARATUS FOR USE IN TUNNELS [75] Inventors: Masahiro Yoshikawa; Yoshio Matsuoka; Kiyotaka Takamatsu, all of Yokohama, Japan [73] Assignee: Mitsui Shipbuilding Company,

Tokyo, Japan [22] Filed: Nov. 14, 1973 [21] Appl. No.: 415,647

[30] Foreign Application Priority Data Nov. 22. 1972 Japan 47-117288 [52] US. Cl. 98/50; 299/12 [51] Int. Cl. E21F l/00 [58] Field of Search 98/49, 50; 299/12 [56] References Cited UNITED STATES PATENTS 1,443,286 1/1923 Smith ct a1 98/49 X 1,578,814 3/1926 DAscenzo 299/12 1,982,470 11/1934 Franks 98/50 x 3,320.765 5/1967 Chapple 61 a1 98/50 x 3,464,756 9/1969 Burgess 299/12 x 3,558,193 1/1971 Howarth 98/50 x FOREIGN PATENTS OR APPLICATIONS 1,066,166 10/1959 Germany 98/50 Primary Ewminer-William F. ODea Assistant E.\'amt'nerPeter D. Ferguson Attorney, Agent, or Firm-Charles W. Helzer [57] ABSTRACT The air circulating apparatus comprises a movable carriage in the form of an arch, an air supply duct mounted on the carriage and provided with an air discharge port for forming an air curtain across the tunnel, and an exhaust duct mounted on the carriage and projecting forwardly. The carriage is provided with crawlers so as to be movable. A sufficient space is left beneath the carriage and the air supply duct for free passage of vehicles.

7 Claims, 4 Drawing Figures US. Patent Nov. 18,1975 Sheet 1 Of?) 3,919,930

US. Patent Nov. 18, 1975 Sheet 2 of3 3,919,930

US. Patent Nov. 18, 1975 Sheet 3 of 3 AIR CIRCULATING APPARATUS FOR USE IN TUNNELS BACKGROUND OF THE INVENTION This invention relates to apparatus for circulating air in a tunnel for exhausting gas evolved in the tunnel near a working face or contaminated air to the outside of the tunnel.

When digging a tunnel gas often evolves near the working face. To exhaust such gas various methods have been used including a method of installing an air duct in the tunnel for admitting air near the working face to diffuse the gas, a method of sucking the gas for exhausting it to the outside, and a method wherein the gas is exhausted while fresh air is supplied through an air duct. Most of these known methods, however, have not been satifactory in that the efficiency of air circulation is low and satisfactory results have not be attained.

SUMMARY OF THE INVENTION An object of this invention is to provide an improved apparatus for circulating fresh air in a tunnel and capable of efficiently exhausting gas evolved not only near the working face but also in the other portions of the tunnel as well as contaminated air and for substituting fresh air.

Another object of this invention is to provide an improved air circulating apparatus for use in a tunnel and capable of forming a small chamber or space substantially sealed by an air curtain. Still another object of this invention is to provide an improved air circulating apparatus which permits free passage of vehicles and workmen through and around the apparatus while the apparatus is in operation.

Yet another object of this invention is to provide a novel air circulating apparatus which is capable of moving to and from the portion in a tunnel that requires air circulation and also is capable of tightly sealing the gap between the apparatus and the inner wall of the tunnel in order to minimize air leakage therebetween.

According to this invention, these and other objects can be accomplished by providing air circulating apparatus for use in a tunnel, comprising a movable carriage, an air supply duct mounted on the carriage and provided with an air discharge port arranged to form an air curtain across the tunnel, and an exhaust duct mounted on the carriage and projecting forwardly beyond the air discharge port of the air supply duct.

The carriage and'the air supply duct extend along the side and upper inner walls of the tunnel so that a suffrcient space is left beneath them to allow free passage of vehicles and workmen while the apparatus is in operation. An inflatable air bag is mounted on the carriage for air tightly sealing the gap between the carriage and the inner walls of the tunnel.

FIG. 3 is a front view of the apparatus shown in FIG. 1; and

2 FIG. 4 is a plan view of an alternate form of the apparatus shown in FIG. 2.

DESCRIPTION OF THE PREFERRED EMBODIMENT The apparatus shown in the accompanying drawing comprises a carriage 1 having a frame work 1a formed in the form of an arch (see FIG. 3) and extending along the side and upper surfaces of tunnel 2. The carriage 1 is provided with wheels or crawlers 3 at the lower portion on both sides for running through the tunnel. An air supply duct 4 is mounted on the carriage 1. The duct 4 is in the form of an arch extending along the side and upper surfaces of the tunnel 2 and is formed with a narrow air discharge slot 5 on the lower surface. The supply end of the air duct 4 is connected to a flexible air duct 6 to receive fresh air from a blower, not shown. An exhaust duct .7 is mounted on the carriage and extends along the side and upper surfaces of the tunnel and then projects forwardly (to the left as viewed in FIG. 1) at the center of the top of the carriage. The exhaust duct 7 is provided with a wide suction port 8 at its outer end. As shown in FIG. 2, the suction pipe 9 of said exhaust duct 7 and provided with the suction port 8, is made independent of the duct 7 and is telescoped thereto. The other end of the exhaust duct 7 is connected to an air duct 10 which is free to expand and contract for exhausting gas and air to the outside by an exhausting device not shown.

The air circulating apparatus of this invention operates as follows: Firstly crawlers 3 are operated to move the apparatus through the tunnel near the working face 11. Then, outside air is supplied to air supply duct 4 through air conduit 6 by operating a blower, not shown. The air supplied to the air supply duct 4 is ejected toward the lower surface of the tunnel through narrow air discharge slot 5 provided for the lower surface of the air duct 4. The air thus ejected forms an air curtain substantially across the entire cross section the tunnel 2 to interrupt air flows between portions in front of and to the rear of this air curtain. In this manner, the working face in the tunnel is isolated by the air curtain to form a small chamber 12. Consequently, gas evolved in chamber 12 at or near the working face is restrained throughout the remainder of the tunnel leading to the work face. Conversely, if there is gas in the tunnel, it is prevented from diffusing into the working face area defined by chamber 2 and is prevented from diffusing.

When an exhaust apparatus, not shown, is operated concurrently with the operation of the blower, the gas evolved and restrained in the chamber 12 by the air curtain is sucked by the suction port 8 of the exhaust duct 7, which can be elongated or contracted as desired, and discharged to the outside through air duct 10. By this exhausting action, air flows forwardly (to the left as viewed in FIG. 1 and as shown by arrow 13) to supplement fresh air drawn into chamber 12 from outside, but it does not modify the action of the air curtain. As a result, a steady flow of air is created and flows to the working face due to the suction port 8 which simultaneously continuously discharges the air mixed with any gas through the suction port 8 without permitting gas or stale air to stay in the chamber 12.

An inflatable air bag 14 is mounted on the carriage 1 for sealing the gap between the apparatus and the inner wall of the tunnel 2, thus preventing more effectively the diffusion of any gas and assuring a positive flow of fresh air to the chamber 12 and withdrawal of substanally, if an elongated air discharge pipe 17 is connected to one end of air duct 14 as shown in FIG. 4, it can be extended closer to the working face for positively supplying fresh air thereto and more efficiently circulate arr.

According to the illustrated example, since the carriage 1, air supply duct 4 and exhaust duct 7 are constructed to lie along the side and upper inner walls of the tunnel 2, a sufficient space is available at the center lower portion of the tunnel for vehicles and workmen. Further, the ventilating apparatus can advance with the working face and retract by a safe distance at the time of explosion of explosives because it is provided with crawlers 3.

While the invention has been explained in connection with a tunnel under construction, it will be clear that the novel air circulation apparatus can also be used for existing tunnels. In the latter case, a single apparatus may be situated on the leeward side, or two apparatus may be situated to form a chamber partitioned by two air curtains.

As above described, the invention provides efficient air circulating apparatus capable of effectively exhausting gas evolved in a tunnel or contaminated air to the outside of the tunnel and can permit free passage of personnel and vehicles.

While the invention has been shown and described in connection with a preferred embodiment thereof it with a framework having upper and side wall members designed to fit within a tunnel and defining a passageway therebetween and said air supply duct means having a corresponding configuration, means for supplying fresh air to the air supply duct means, said air supply duct means including air discharge port means for forming a fresh air curtain across the passageway defined by the framework and air supply duct means, exhaust duct means mounted on safe carriage and pro- 10 jecting forwardly beyond the fresh air curtain for exhausting gases and stale air from space closed by the fresh air curtain, and means mounted on said framework for forming a substantially airtight seal between the framework and the sides and roof of a tunnel or other enclosed space in which the apparatus is used.

2. An air circulating apparatus according to claim 1 wherein said carriage is provided with a pair of crawlers at the bottom on both sides thereof and a passageway is provided therebetween to accommodate passage of personnel and vehicles.

3. An air circulating apparatus according to claim 2 wherein said air discharge port means comprises a narrow arcuate slot formed in the undersurface of the air supply duct means for forming the fresh air curtain across the passageway.

4. The air circulating apparatus according to claim 3 wherein said exhaust duct means includes an extendable suction port telescopically fitted to said exhaust duct means.

5. An air circulating apparatus according to claim 4 wherein said air supply duct means includes an additional air discharge supply pipe extending forwardly into the space closed by the fresh air curtain.

6. An air circulating apparatus according to claim 5 further comprising blower means mounted on said carriage for supplying fresh air to said air supply duct means.

7. An air circulating apparatus according to claim 6 wherein said airtight seal forming means comprises an inflatable air bag adapted to seal the gap between said upper and side members of the framework and the inner roof and sidewalls of a tunnel or other enclosed space in which the apparatus is used. 

1. Air circulating apparatus for use in a tunnel comprising a movable carriage, air supply duct means mounted on said carriage, said carriage being provided with a framework having upper and side wall members designed to fit within a tunnel and defining a passageway therebetween and said air supply duct means having a corresponding configuration, means for supplying fresh air to the air supply duct means, said air supply duct means including air discharge port means for forming a fresh air curtain across the passageway defined by the framework and air supply duct means, exhaust duct means mounted on safe carriage and projecting forwardly beyond the fresh air curtain for exhausting gases and stale air from space closed by the fresh air curtain, and means mounted on said framework for forming a substantially airtight seal between the framework and the sides and roof of a tunnel or other enclosed space in which the apparatus is used.
 2. An air circulating apparatus according to claim 1 wherein said carriage is provided with a pair of crawlers at the bottom on both sides thereof and a passageway is provided therebetween to accommodate passage of personnel and vehicles.
 3. An air circulating apparatus according to claim 2 wherein said air discharge port means comprises a narrow arcuate slot formed in the undersurface of the air supply duct means for forming the fresh air curtain across the passageway.
 4. The air circulating apparatus according to claim 3 wherein said exhaust duct means includes an extendable suction port telescopically fitted to said exhaust duct means.
 5. An air circulating apparatus according to claim 4 wherein said air supply duct means includes an additional air discharge supply pipe extending forwardly into the space closed by the fresh air curtain.
 6. An air circulating apparatus according to claim 5 further comprising blower means mounted on said carriage for supplying fresh air to said air supply duct means.
 7. An air circulating apparatus according to claim 6 wherein said airtight seal forming means comprises an inflatable air bag adapted to seal the gap between said upper and side members of the framework and the inner roof and sidewalls of a tunnel or other enclosed space in which the apparatus is used. 